Employee Benefits, Defined Benefit Plans Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued Annual Veba Contribution	$ 2.1	$ 15.7
Defined Benefit Plan, Plan Assets, Amount	68.1	72.3
Union VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued Annual Veba Contribution		12.8
Salaried VEBA
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued Annual Veba Contribution	2.1	2.9
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year	5.7
Defined Benefit Plan, Expected Amortization, Next Fiscal Year	6.1
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year	0.4
VEBAs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation	85.6	90.0	$ 86.8
Defined Benefit Plan, Plan Assets, Amount	53.2	58.1	58.2
Salaried and certain hourly employee | Canadian pension plan | Maximum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated annual contribution to pension and other postretirement benefit plans	2.9
Canadian pension plan | Canadian pension plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Benefit Obligation	7.3	8.5	7.0
Defined Benefit Plan, Plan Assets, Amount	6.5	7.3	$ 6.1
Defined Benefit Plan, Accumulated Benefit Obligation	6.4	$ 7.9
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 0.6
London Ontario Facility | Canadian pension plan | Canadian pension plan | Fixed Income Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	34.00%
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	30.00%
London Ontario Facility | Canadian pension plan | Canadian pension plan | Equity Securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	62.00%
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	65.00%
London Ontario Facility | Canadian pension plan | Canadian pension plan | Short-term Investments
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	5.00%